'use strict';

const autoprefixer = require('autoprefixer');
const path = require('path');
const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const ManifestPlugin = require('webpack-manifest-plugin');
const InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
const SWPrecacheWebpackPlugin = require('sw-precache-webpack-plugin');
const eslintFormatter = require('react-dev-utils/eslintFormatter');
const ModuleScopePlugin = require('react-dev-utils/ModuleScopePlugin');
const paths = require('./paths');
const getClientEnvironment = require('./env');
const postcssAspectRatioMini = require('postcss-aspect-ratio-mini');
const postcssPxToViewportOpt = require('postcss-px-to-viewport-opt');
const postcssWriteSvg = require('postcss-write-svg');
const postcssViewportUnits = require('postcss-viewport-units');

// Webpack uses `publicPath` to determine where the app is being served from.
// It requires a trailing slash, or the file assets will get an incorrect path.
const publicPath = paths.servedPath;
// Some apps do not use client-side routing with pushState.
// For these, "homepage" can be set to "." to enable relative asset paths.
const shouldUseRelativeAssetPaths = publicPath === './';
// Source maps are resource heavy and can cause out of memory issue for large source files.
const shouldUseSourceMap = process.env.GENERATE_SOURCEMAP !== 'false';
// `publicUrl` is just like `publicPath`, but we will provide it to our app
// as %PUBLIC_URL% in `index.html` and `process.env.PUBLIC_URL` in JavaScript.
// Omit trailing slash as %PUBLIC_URL%/xyz looks better than %PUBLIC_URL%xyz.
const publicUrl = publicPath.slice(0, -1);
// Get environment variables to inject into our app.
const env = getClientEnvironment(publicUrl);

// Assert this just to be safe.
// Development builds of React are slow and not intended for production.
if (env.stringified['process.env'].NODE_ENV !== '"production"') {
	throw new Error('Production builds must have NODE_ENV=production.');
}

// Note: defined here because it will be used more than once.
const cssFilename = 'static/css/[name].[contenthash:8].css';

// ExtractTextPlugin expects the build output to be flat.
// (See https://github.com/webpack-contrib/extract-text-webpack-plugin/issues/27)
// However, our output is structured with css, js and media folders.
// To have this structure working with relative paths, we have to use custom options.
const extractTextPluginOptions = shouldUseRelativeAssetPaths
	? // Making sure that the publicPath goes back to to build folder.
	{publicPath: Array(cssFilename.split('/').length).join('../')}
	: {};

// This is the production configuration.
// It compiles slowly and is focused on producing a fast and minimal bundle.
// The development configuration is different and lives in a separate file.
module.exports = {
	// Don't attempt to continue if there are any errors.
	bail: true,
	// We generate sourcemaps in production. This is slow but gives good results.
	// You can exclude the *.map files from the build during deployment.
	devtool: shouldUseSourceMap ? 'source-map' : false,
	// In production, we only want to load the polyfills and the app code.
	entry: [require.resolve('./polyfills'), paths.appIndexJs],
	output: {
		// The build folder.
		path: paths.appBuild,
		// Generated JS file names (with nested folders).
		// There will be one main bundle, and one file per asynchronous chunk.
		// We don't currently advertise code splitting but Webpack supports it.
		filename: 'static/js/[name].[chunkhash:8].js',
		chunkFilename: 'static/js/[name].[chunkhash:8].chunk.js',
		// We inferred the "public path" (such as / or /my-project) from homepage.
		publicPath: publicPath,
		// Point sourcemap entries to original disk location (format as URL on Windows)
		devtoolModuleFilenameTemplate: info =>
			path
				.relative(paths.appSrc, info.absoluteResourcePath)
				.replace(/\\/g, '/'),
	},
	resolve: {
		// This allows you to set a fallback for where Webpack should look for modules.
		// We placed these paths second because we want `node_modules` to "win"
		// if there are any conflicts. This matches Node resolution mechanism.
		// https://github.com/facebookincubator/create-react-app/issues/253
		modules: ['node_modules', paths.appNodeModules].concat(
			// It is guaranteed to exist because we tweak it in `env.js`
			process.env.NODE_PATH.split(path.delimiter).filter(Boolean)
		),
		// These are the reasonable defaults supported by the Node ecosystem.
		// We also include JSX as a common component filename extension to support
		// some tools, although we do not recommend using it, see:
		// https://github.com/facebookincubator/create-react-app/issues/290
		// `web` extension prefixes have been added for better support
		// for React Native Web.
		extensions: ['.web.js', '.mjs', '.js', '.json', '.web.jsx', '.jsx'],
		alias: {
			
			// Support React Native Web
			// https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
			'react-native': 'react-native-web',
		},
		plugins: [
			// Prevents users from importing files from outside of src/ (or node_modules/).
			// This often causes confusion because we only process files within src/ with babel.
			// To fix this, we prevent you from importing files out of src/ -- if you'd like to,
			// please link the files into your node_modules/ and let module-resolution kick in.
			// Make sure your source files are compiled, as they will not be processed in any way.
			new ModuleScopePlugin(paths.appSrc, [paths.appPackageJson]),
		],
	},
	module: {
		strictExportPresence: true,
		rules: [
			// TODO: Disable require.ensure as it's not a standard language feature.
			// We are waiting for https://github.com/facebookincubator/create-react-app/issues/2176.
			// { parser: { requireEnsure: false } },
			
			// First, run the linter.
			// It's important to do this before Babel processes the JS.
			{
				test: /\.(js|jsx|mjs)$/,
				enforce: 'pre',
				use: [
					{
						options: {
							formatter: eslintFormatter,
							eslintPath: require.resolve('eslint'),
							
						},
						loader: require.resolve('eslint-loader'),
					},
				],
				include: paths.appSrc,
			},
			{
				// "oneOf" will traverse all following loaders until one will
				// match the requirements. When no loader matches it will fall
				// back to the "file" loader at the end of the loader list.
				oneOf: [
					// "url" loader works just like "file" loader but it also embeds
					// assets smaller than specified size as data URLs to avoid requests.
					{
						test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
						loader: require.resolve('url-loader'),
						options: {
							limit: 10000,
							name: 'static/media/[name].[hash:8].[ext]',
						},
					},
					// Process JS with Babel.
					{
						test: /\.(js|jsx|mjs)$/,
						include: paths.appSrc,
						loader: require.resolve('babel-loader'),
						options: {
							
							compact: true,
						},
					},
					// The notation here is somewhat confusing.
					// "postcss" loader applies autoprefixer to our CSS.
					// "css" loader resolves paths in CSS and adds assets as dependencies.
					// "style" loader normally turns CSS into JS modules injecting <style>,
					// but unlike in development configuration, we do something different.
					// `ExtractTextPlugin` first applies the "postcss" and "css" loaders
					// (second argument), then grabs the result CSS and puts it into a
					// separate file in our build process. This way we actually ship
					// a single CSS file in production instead of JS code injecting <style>
					// tags. If you use code splitting, however, any async bundles will still
					// use the "style" loader inside the async code so CSS from them won't be
					// in the main CSS file.
					{
						test: /\.css$/,
						loader: ExtractTextPlugin.extract(
							Object.assign(
								{
									fallback: {
										loader: require.resolve('style-loader'),
										options: {
											hmr: false,
										},
									},
									use: [
										{
											loader: require.resolve('css-loader'),
											options: {
												importLoaders: 1,
												minimize: true,
												sourceMap: shouldUseSourceMap,
											},
										},
										{
											loader: require.resolve('postcss-loader'),
											options: {
												// Necessary for external CSS imports to work
												// https://github.com/facebookincubator/create-react-app/issues/2677
												ident: 'postcss',
												plugins: () => [
													require('postcss-flexbugs-fixes'),
													autoprefixer({
														browsers: [
															'>1%',
															'last 4 versions',
															'Firefox ESR',
															'not ie < 9', // React doesn't support IE8 anyway
														],
														flexbox: 'no-2009',
													}),
												],
											},
										},
									],
								},
								extractTextPluginOptions
							)
						),
						// Note: this won't work without `new ExtractTextPlugin()` in `plugins`.
					},
					{
						test: /\.(css|less)$/,
						exclude: [/node_modules/],
						loader: ExtractTextPlugin.extract(
							Object.assign(
								{
									fallback: {
										loader: require.resolve('style-loader'),
										options: {
											hmr: false,
										},
									},
									use: [
										{
											loader: require.resolve('css-loader'),
											options: {
												importLoaders: 1,
												minimize: true,
												sourceMap: shouldUseSourceMap,
												modules: true,
											},
										},
										{
											loader: require.resolve('postcss-loader'),
											options: {
												// Necessary for external CSS imports to work
												// https://github.com/facebookincubator/create-react-app/issues/2677
												ident: 'postcss',
												plugins: () => [
													require('postcss-flexbugs-fixes'),
													autoprefixer({
														browsers: [
															'>1%',
															'last 4 versions',
															'Firefox ESR',
															'not ie < 9', // React doesn't support IE8 anyway
														],
														flexbox: 'no-2009',
													}),
													postcssAspectRatioMini({}),
													postcssPxToViewport({
														viewportWidth: 750, // (Number) The width of the viewport.
														viewportHeight: 1334, // (Number) The height of the viewport.
														unitPrecision: 3, // (Number) The decimal numbers to allow the REM units to grow to.
														viewportUnit: 'vw', // (String) Expected units.
														selectorBlackList: ['.ignore', '.hairlines'], // (Array) The selectors to ignore and leave as px.
														minPixelValue: 1, // (Number) Set the minimum pixel value to replace.
														mediaQuery: false, // (Boolean) Allow px to be converted in media queries.
														exclude: /(\/|\\)(node_modules)(\/|\\)/
													}),
													postcssWriteSvg({
														utf8: false
													}),
													postcssViewportUnits({}),
												],
											},
										},
										{
											loader: require.resolve('less-loader')
										}
									],
								},
								extractTextPluginOptions
							)
						),
						// Note: this won't work without `new ExtractTextPlugin()` in `plugins`.
					},
					// "file" loader makes sure assets end up in the `build` folder.
					// When you `import` an asset, you get its filename.
					// This loader doesn't use a "test" so it will catch all modules
					// that fall through the other loaders.
					{
						loader: require.resolve('file-loader'),
						// Exclude `js` files to keep "css" loader working as it injects
						// it's runtime that would otherwise processed through "file" loader.
						// Also exclude `html` and `json` extensions so they get processed
						// by webpacks internal loaders.
						exclude: [/\.(js|jsx|mjs)$/, /\.html$/, /\.json$/],
						options: {
							name: 'static/media/[name].[hash:8].[ext]',
						},
					},
					// ** STOP ** Are you adding a new loader?
					// Make sure to add the new loader(s) before the "file" loader.
				],
			},
		],
	},
	plugins: [
		// Makes some environment variables available in index.html.
		// The public URL is available as %PUBLIC_URL% in index.html, e.g.:
		// <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
		// In production, it will be an empty string unless you specify "homepage"
		// in `package.json`, in which case it will be the pathname of that URL.
		new InterpolateHtmlPlugin(env.raw),
		// Generates an `index.html` file with the <script> injected.
		new HtmlWebpackPlugin({
			inject: true,
			template: paths.appHtml,
			minify: {
				removeComments: true,
				collapseWhitespace: true,
				removeRedundantAttributes: true,
				useShortDoctype: true,
				removeEmptyAttributes: true,
				removeStyleLinkTypeAttributes: true,
				keepClosingSlash: true,
				minifyJS: true,
				minifyCSS: true,
				minifyURLs: true,
			},
		}),
		// Makes some environment variables available to the JS code, for example:
		// if (process.env.NODE_ENV === 'production') { ... }. See `./env.js`.
		// It is absolutely essential that NODE_ENV was set to production here.
		// Otherwise React will be compiled in the very slow development mode.
		new webpack.DefinePlugin(env.stringified),
		// Minify the code.
		new webpack.optimize.UglifyJsPlugin({
			compress: {
				warnings: false,
				// Disabled because of an issue with Uglify breaking seemingly valid code:
				// https://github.com/facebookincubator/create-react-app/issues/2376
				// Pending further investigation:
				// https://github.com/mishoo/UglifyJS2/issues/2011
				comparisons: false,
			},
			mangle: {
				safari10: true,
			},
			output: {
				comments: false,
				// Turned on because emoji and regex is not minified properly using default
				// https://github.com/facebookincubator/create-react-app/issues/2488
				ascii_only: true,
			},
			sourceMap: shouldUseSourceMap,
		}),
		// Note: this won't work without ExtractTextPlugin.extract(..) in `loaders`.
		new ExtractTextPlugin({
			filename: cssFilename,
		}),
		// Generate a manifest file which contains a mapping of all asset filenames
		// to their corresponding output file so that tools can pick it up without
		// having to parse `index.html`.
		new ManifestPlugin({
			fileName: 'asset-manifest.json',
		}),
		// Generate a service worker script that will precache, and keep up to date,
		// the HTML & assets that are part of the Webpack build.
		new SWPrecacheWebpackPlugin({
			// By default, a cache-busting query parameter is appended to requests
			// used to populate the caches, to ensure the responses are fresh.
			// If a URL is already hashed by Webpack, then there is no concern
			// about it being stale, and the cache-busting can be skipped.
			dontCacheBustUrlsMatching: /\.\w{8}\./,
			filename: 'service-worker.js',
			logger(message) {
				if (message.indexOf('Total precache size is') === 0) {
					// This message occurs for every build and is a bit too noisy.
					return;
				}
				if (message.indexOf('Skipping static resource') === 0) {
					// This message obscures real errors so we ignore it.
					// https://github.com/facebookincubator/create-react-app/issues/2612
					return;
				}
				console.log(message);
			},
			minify: true,
			// For unknown URLs, fallback to the index page
			navigateFallback: publicUrl + '/index.html',
			// Ignores URLs starting from /__ (useful for Firebase):
			// https://github.com/facebookincubator/create-react-app/issues/2237#issuecomment-302693219
			navigateFallbackWhitelist: [/^(?!\/__).*/],
			// Don't precache sourcemaps (they're large) and build asset manifest:
			staticFileGlobsIgnorePatterns: [/\.map$/, /asset-manifest\.json$/],
		}),
		// Moment.js is an extremely popular library that bundles large locale files
		// by default due to how Webpack interprets its code. This is a practical
		// solution that requires the user to opt into importing specific locales.
		// https://github.com/jmblog/how-to-optimize-momentjs-with-webpack
		// You can remove this if you don't use Moment.js:
		new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
	],
	// Some libraries import Node modules but don't use them in the browser.
	// Tell Webpack to provide empty mocks for them so importing them works.
	node: {
		dgram: 'empty',
		fs: 'empty',
		net: 'empty',
		tls: 'empty',
		child_process: 'empty',
	},
};
